This invention relates to apparatus for measuring the rate of flow of a fluid through a conduit and, more particularly, to such apparatus which provides an electronic signal compatible with present day electronic controls.
There are many applications where it is desired to control the flow of a fluid through a conduit in order to fill a container with a desired amount of the fluid. For example, in an appliance such as a clothes washing machine, the user may select a desired water level depending upon the size of the load being washed. It is conventional to provide such control through electromechanical technology that provides fill level control through pressure switches, time fill or through limit switch control by a float. With the advent of microcomputer control of appliances, many of the control functions previously handled by electromechanical devices have been taken over by the microcomputer. It would be desirable for the microcomputer to control the water level in such an appliance. It is therefore an object of the present invention to provide apparatus through which a microcomputer based system can control fluid level.
Fluid level can be directly measured in a number of ways such as, for example, by providing a plurality of level sensors at different levels of the fluid container. However, it would be desirable to reduce the number of required sensors and to be able to take advantage of the computing power of the microcomputer. Since fluid level may also be measured by knowing the rate at which fluid enters the container and then integrating this rate with respect to time, only a single flow rate sensor coupled between a conduit feeding the container and the microcomputer is required. It is therefore a further object of this invention to provide a fluid flow rate sensor.